Seismic isolator

Abstract

A seismic isolator comprising: a first and a second plate-like coupling member which are arranged substantially horizontally one spaced apart above the other; and a movable sliding-block which is interposed between said plate-like coupling members, and rests in a freely sliding manner on the concave bottom of a depression realized on the exposed face of said first plate-like coupling member; the concave bottom being provided with at least one free-sliding area, which surrounds/flanks the stationary-standing area and is provided with a dynamic friction coefficient greater than that of the stationary-standing area.

1 . A seismic isolator comprising:
 a first and a second plate-like coupling member which are arranged substantially horizontally one spaced apart above the other; and a movable sliding-block which is interposed between said plate-like coupling members, and rests in free sliding manner on the concave bottom of a depression realized on the exposed face of said first plate-like coupling member;   the seismic isolator being characterized in that the movable sliding-block rests in a free sliding manner on said concave bottom, within the perimeter of a given stationary-standing area ( 6   a ) having an extent smaller than the overall extent of the concave bottom; and   in that the concave bottom additionally has at least one free-sliding area which surrounds/flanks said stationary-standing area and is provided with a dynamic friction coefficient greater than that of the stationary-standing area; the movable sliding-block being able to freely slide on the concave bottom of the depression also above said free-sliding area.   
     
     
         2 . Seismic isolator according to  claim 1 , characterized in that the concave bottom has a radius of curvature substantially constant. 
     
     
         3 . Seismic isolator according to  claim 2 , characterized in that said concave bottom is shaped substantially like a spherical dome, and in that the stationary-standing area is located substantially at the centre of said concave bottom. 
     
     
         4 . Seismic isolator according to  claim 3 , characterized in that said at least one free-sliding area is annular in shape and completely surrounds the stationary-standing area. 
     
     
         5 . Seismic isolator according to  claim 1 , characterized in that the concave bottom has a plurality of free-sliding areas which surround/flank said stationary-standing area and are provided with a dynamic friction coefficient greater than that of the stationary-standing area; the movable sliding-block being able to freely slide on the concave bottom of the depression also above said free-sliding areas. 
     
     
         6 . Seismic isolator according to  claim 5 , characterized in that the free-sliding areas are adjacent/adjoined to each other. 
     
     
         7 . Seismic isolator according to  claim 5 , characterized in that the value of the dynamic friction coefficient increases as the distance of the free-sliding area from the stationary-standing area raises. 
     
     
         8 . Seismic isolator according to  claim 1 , characterized in that the movable sliding-block rests in free sliding manner also on the exposed face of said second plate-like coupling member. 
     
     
         9 . Seismic isolator according to  claim 1 , characterized in that the movable sliding-block is rigidly integral with said second plate-like coupling member. 
     
     
         10 . Seismic isolator according to  claim 1 , characterized in that said first plate-like coupling member is made of metal material and/or in that said second plate-like coupling member is made of metal material. 
     
     
         11 . Seismic isolator according to  claim 1 , characterized in that said movable sliding-block is made of metal material or plastic material or composite material. 
     
     
         12 . Seismic isolator according to  claim 1 , characterized in that said first plate-like coupling member is adapted to be stably anchored to the ground or to another supporting surface, and in that said second plate-like coupling member is adapted to be stably anchored beneath the superstructure of the building or other body to be seismically isolated.